1. Field of the Invention
Embodiments of the present invention generally relate to communication systems. In particular, example embodiments relate to an optical network unit (ONU) transceiver module configured to provide a number of features such as ensuring I/O pin alignment, preventing tilting, and/or positioning the top of the ONU transceiver module at a predetermined height above a host printed circuit board (PCB) having a protruding socket.
2. Related Technology
Interest in broadband optical access networks is growing, driven by an increasing demand for high-speed multimedia services. Optical access networks are often referred to as fiber-to-the-curb (FTTC), fiber-to-the-building (FTTB), fiber-to-the-premise (FTTP), or fiber-to-the-home (FTTH). Each such network provides an access from a central office to a building, or a home, via optical fibers in an optical cable. As the transmission quantity of such an optical cable is much greater than the bandwidth actually required by each subscriber, passive optical networks (PON) shared between many subscribers through splitters have been developed.
Referring to FIGS. 1A and 1B, a conventional ONU transceiver module 100 and host device 102 are shown. The ONU transceiver module 100 includes input/output (I/O) pins 104 that are plugged into the host device's 102 internal PCB 106. The ONU transceiver module includes an RF connector 108 for an RF cable to connect to the ONU transceiver module 100. More specifically, typical ONU transceiver modules 100 have 20 I/O pins in a row protruding from the bottom of the ONU transceiver modules 100 and the standard RF connector 108 for transmission of an electrical video signal. One example of a standard RF connector used is a SubMiniature B (SMB) connector that protrudes from a side of the ONU transceiver module 100.
The host device 102 includes a protruding connector 110 configured to receive the I/O pins 104 of the ONU transceiver module 100. Because the protruding connector 110 extends above the PCB 106, the module 100 has to be raised to a height which is at the same level as the protruding connector 110 to prevent tilting when the module 100 is plugged into the host device 102. Additionally, proper functioning requires that the I/O pins 104 are plugged into the correct holes of the protruding socket 110.
The conventional module 100 of FIG. 1A includes various features to address these two problems, including a plurality of stepped guide pins 112A-112C and a stabilizing rib 114. Each of the stepped guide pins 112A-112C includes a guiding pin 116A-116C and a stepped portion 118A-118C. The stepped portions 118A-118C and stabilizing rib 114 are configured to rest on the host device 102 PCB 106 to raise the module 100 to the same level as the protruding connector 110 to prevent tilting when the module 100 is plugged into the host device 102. The guiding pins 116A-116C are configured to be received by guiding holes 120A-120C on the host PCB 106; alignment of the guiding pins 116A-116C with the guiding holes 120A-120C aligns the I/O pins 104 with the corresponding holes of the protruding I/O socket 110. After aligning the guiding pins 116A-116C with the guiding holes 120A-120C, the guiding pins 116A-116C can be received in the guiding holes 120A-120C, allowing the I/O pins 104 to then be inserted into the correct holes of the protruding I/O socket 110.
Each of the stepped guide pins 112A-112C is a separate component that increases the number of separate parts used in assembling the module 100. Generally speaking, each additional part used in module 100 assembly not only increases the cost of the module 100, but also increases the processes required to assemble the finished product. Moreover, in the conventional module 100 of FIG. 1A, holes are formed in the module 100 to receive each of the stepped guiding pins 112A-112C—these holes can weaken the shell structure of the module 100. Furthermore, the guiding pins 116A-116C are relatively long compared to their diameter such that the guiding pins 116A-116C may be susceptible to breaking or bending.
The host device 102 further includes a plurality of posts 122A and 122B configured to be coupled to a heatsink (not shown) to dissipate heat away from the module 100. For the heatsink to operate effectively, the module 100 must be positioned at a predetermined height above the PCB 106 when the module 100 is plugged into the host device 102. Module designs that do not meet the height requirement have to be raised or lowered to ensure proper contact with the heatsink.